Pakistani troops have been told to "shoot on sight" if need be to control political violence in the southern city of Karachi. Pakistani authorities have banned political rallies in the city, where at least 38 people were killed in two days of street battles between government and opposition supporters. VOA correspondent Benjamin Sand reports from Islamabad.

Officials in Karachi say they are doing everything they can to prevent another outbreak of violence.

The government banned demonstrations and thousands of paramilitary forces have been deployed throughout the port city.

The government on Sunday gave the troops authority to shoot on sight to halt clashes between pro-government activists and supporters of the country's suspended chief justice, Iftakhar Chaudhry.

Opposition leaders called a nationwide strike on Monday and shops in major cities throughout the country were closed.

Senator Fahatullah Babar, a spokesman for the opposition Pakistan People's Party, says President Pervez Musharraf bears responsibility for the recent violence.

"Today's strike is an expression of the complete lack of trust in the man," he said. "The present regime has utterly failed to deliver and people now want a change of guard to fair and free elections."

Supporters of Pakistani opposition party run after setting on fire a vehicle during a gun battle between two rival groups in Karachi, 12 May 2007

Witnesses say government forces made no effort to control the violence as it swept through the city, ultimately forcing Chaudhry to abandon plans to address a public rally.

President Musharraf suspended the chief justice two months ago on charges of misconduct.

The judge's supporters say the president removed Chaudhry to reassert control over the increasingly independent judiciary.

The legal community and political opposition have mounted increasingly confrontational rallies to protest Chaudhry's removal.

Political analysts here say the standoff is the greatest challenge to General Musharraf since he took power in 1999 military coup.

Rasul Bahksh Rais is a professor of political science at the Lahore University of Management Sciences. He says public support for the president is at an all time low and Mr. Musharraf has lost the political capacity to defend himself.

"He can prolong and linger on, but I don't think he has got any good options to defuse the situation," he said.

President Musharraf is expected to seek another five-year term in office from Pakistan's national assembly later this year.

His critics say the move is unconstitutional and vow to challenge it in Pakistan's Supreme Court.